1. Field of the Invention
The present invention relates to a drive method of a liquid crystal display and, more particularly, to a method for driving an antiferroelectric liquid crystal display.
2. Description of Related Art
Generally, in a conventional antiferroelectric liquid crystal display, a white mode is realized when liquid crystal molecules undergo a phase-transition into one of a positive ferroelectric phase (hereinafter, referred to as "F+phase") by positive voltage and a negative ferroelectric phase (hereinafter, referred to as "F-phase") by negative voltage, while a black mode is realized when the liquid crystal molecules undergo a phase-transition into an antiferroeletric phase (hereinafter, referred to as "AF phase") when no voltage is applied.
Describing more in detail, to realize the white mode, the liquid crystal molecules alternately undergo a phase-transition into the F+phase and the F-phase by one frame cycle, and the time for one frame cycle is set at less than 30 ms, at which the frame is invisible, to prevent the flicker of images.
However, in the above described antiferroelectric liquid crystal display, if a viewing angle is inclined from a direction normal to an activated pixel on a screen, since directions of the F-phase and the F+phase are different from each other as shown in FIG. 1, light transmittance with respect to the viewing angle becomes different, causing flicker of images on he screen.
To prevent flicker, the time for two frame cycles for repeating the +phase and the F-phase should be set at less than 30 ms. That is, one frame cycle should take less than 15 ms.
However, since present technology cannot increase a drive frequency of a drive device of the liquid crystal display above tens of MHz, it is impossible to realize a high color moving picture. Therefore, it is very costly and time-consuming to develop a drive device that can realize 15 ms frame cycle.
Therefore, the conventional antiferroelectric liquid crystal display displaying an image using the F+phase and the F-phase cannot solve the flicker problem unless the frame cycle is reduced to less than 15 ms.